This is an attempt at discovering groups of songs with similar trends as they moved on weekly British Top 40 Chart from 1990 to 2014.
A total of 1284 different songs appeared on the charts in that period.
After a series of experiments, 100 groups were arbitrarily decided on. Position data for each song was collected across the weeks, then the songs were grouped using k-means clustering.
The result is in these charts.

The top chart is interactive. Move mouse over lines to discover artist, title and entry and exit dates from the charts.
To select a different group (cluster), use the "Previous" and "Next" links on top, or click any of small charts below.
Bottom charts are just small multiples of all hundred clusters. The titles above them are just artist and title of the first song in group.